PROJECT SUMMARY/ABSTRACT Smoking is the leading preventable cause of death and disease in the US. Many cigarette smokers have taken up e-cigarettes hoping to reduce their health risks. Yet, more than half of the 11 million current e- cigarette users in the US continue to smoke combustible cigarettes. Contrary to what these dual users of cigarettes and e-cigarettes may expect, replacing only some combustible cigarette use with e-cigarettes appears to have little health benefit?dual users are exposed to many toxins at similar or higher levels than exclusive cigarette smokers. Dual users need to be informed of their continued risk from smoking combustible cigarettes as well as the known harms of e-cigarettes. They should be encouraged to quit cigarettes and ultimately e-cigarettes. Helping smokers end use of combustible tobacco is central to FDA's new comprehensive plan for nicotine and tobacco. No research exists, however, on how to create communication campaign messages specifically for dual cigarette and e-cigarette users. In this project, my goal is to develop communication campaign messages for dual users that increase their knowledge of the high health risk of dual use and increase their intent to quit combustible cigarettes and ultimately e-cigarettes. Aim 1 develops effective campaign messages by investigating how dual users think about their identity, motivations for tobacco product use, and the barriers to quitting combustible cigarettes. I first use focus groups to understand dual users and gather concepts for messages. Using these findings and existing literature, I then draft 50-75 potential campaign messages for dual users to encourage them to quit, and use a national survey with 1,008 adults to select the most promising campaign message themes. Aim 2 determines whether campaign ads are more engaging if they focus on quitting combustible cigarettes only, sequentially quitting cigarettes and e-cigarettes, or simultaneously quitting cigarettes and e-cigarettes. I create visual ads for the messages from Aim 1 and use an eye-tracking experiment to determine how the different conditions affect attention among dual users. Aim 3 pilot tests the effectiveness of campaign ads sent via texting in changing real-world combustible cigarette and e-cigarette quit intention among dual users. The proposed research and training move me toward my career goal of becoming an independent behavioral scientist advancing health communications that support tobacco regulations. I will learn the applied theory of the psychology of identity and persuasion, the content areas of nicotine and cessation science, and the skills of eye-tracking methodology and message development and testing. The grant's findings will be directly relevant to communication about cigarettes and e-cigarettes and will also add to the broader tobacco communication science. The K01 will inform an R01 proposal for a full-scale RCT testing the effectiveness of campaign ads for dual users to encourage them in quitting.